Revolution-counter.



H. H. CUMMINGS.

REVOLUTION COUNTER.

APPLICATloN FILED AuG.2B ,1912.

Patented Apr. 17, 1917.

5 SHEETS-SHEET l. lg. j

H. H. CUNHVHNGS.

REVOLUTION COUNTER.

APPLICATION FILED AUG.28|1912.

1,223,039. Patented Apr. 17, 1917.

5 SHEETS-SHEET 2.

H. H. CUMNHNGS.

REVOLUTION COUNTER.

APPLICATION FILED Aue.28. I9I2.

Patented Apr. 17,V 1917.

5 SHEETS-SHEET 3.

H. H. CUMIVHNGS.

REVOLUTION COUNTER.

APPLICATION `FILED AuG.2B. 1912.

5 SHEETS-SHEET 5.

PM AVERAGE MM2/5565: lmvezof UNITED STATES PATENT OFFICE.'

y HENRY H. CUMMINGS, OF NEWTON, MASSACHUSETTS.

REVOLUTION-COUNTER.

Specification of Letters Patent.

Application led August 28, 1912. Serial No. 717,453.

average revolutions ofsevera-l revolving members as Well as the averagerevolutions e per minute of several such members.

It is an especial object of my invention to provide an accurate andeificientcounter and indicator which shall not only indicate therevolutions of each of several rotating members but which will alsoautomatically count and indicateaccurately the average number ofrevolutions of a plurality of such members, whether all said members areactually in rotation, whether they are movmig ln-the same or differentdirections, and w e ther they are movingat the same or at,y differentrates of speed. My invention comprises means to countend indicate theresultant average revolutions of a plurality of rotating membersirrespective of their individual directions or rates of movement andthis feature ofthe invention, so fareas I am aware, is broadly new and Idesire to claim it broadly. V

A further important object of the invention is to provide means whichshall count and indicate the number of revolutions per minute of one orthe average of a plurality of rotating members during any predeterminedspace of time. Thus if it is desired to note the average revolutions ofa plurality of revolving parts and to count and indicate suchaveragerevolutions per minute, quickly, in a less time than one minute,as thirty seconds, my invention contemplates means to so count andindicate such an average, irrespective of whether the several rotatingmembers are moving in the same or in different directions and at thesame or at different speeds lor if some only of said members are inmotion and the Aother or others are at rest.

A further feature of the invention is the provision of means to countand indicate the average revolutions per minute of one or of aplurality' of revolving members such average to be the resultant `of agreater length of time than one minute such forgexample as counting andindicating the averperiodl of five minutes. the invention whereby theaveragerevolutionsper minute of one or more revolving parts is countedor indicated for a less period or a greater period, or any predeterminedspace of time is also believed to be a distinct noveltyl in the art towhich this invention relates and it is desired to claim these featuresbroadly.

The advantages of thus counting and inatented Apr. 17, 1917.

" age revolutions'for one minute during al@ These features of dicatingthe average revolutions per minute, and of counting and.v indicating theaverage revolutions per minute during any predetermined space of time,of.a plurality of rotating members is of great importance. Thus, forexample, in the m ern naval vessel where it is customary to ave three,or even four, propelling shafts and screws,- it is customary andnecessary to count the revolutions of each shaft as the speed of thevessel is usually reckoned with accuracy from the revolutions of thepropellingshafts and my inventionltherefore which automatically countsand indicates the average revolutions of several shafts aswell astheaverage revolutions per minute, saves all the calculating andmathematical averaging formerly required as well as the tlme 1nvolved insuch calculations and thus indicates instantly the desired averageresults with `perfect accuracy. Also the average revolutions vper minutecan be obtained ,alf

most as quickly viz. in thirty seconds. It will be `readily understoodthat 1n maneuvering a. Heet of vessels at sea the accuracy andeectivenessof such maneuvers will be greatly facilitated by the averageindicator i value of my invention which producesvthe desired resultantaverage instantly and without-chance for error will be manifest.

responding number of the propelling shafts of a ship, each indicatorserving 'as a counter for the revolutions of its respective propellingshaft and an additional average counter so connected. with the actuatingmember of each individual indicator as to operate the average counterwith a motion exactly equivalent tothe resultant average of all theother shafts, irrespective of their directions of movement and rates ofspeed. 'llhus if all the shafts are going in one direction but atdierent speeds so as to drive the ship ahead,-'my invention` includessuch compensating and differentiating means as to give the resultantaverage 1f one engine is moving to drivelthe vessel ahead and two othersare reversing to drive the ship astern then the resultant average,whether to produce a forward or backward movement or to hold the shiplstationary, will be automatically indicated by the average counter. 1fone engine is going at a speed in one direction suiiicient to more thancounteract the slower speeds of the other engines in the reversedirection then such averaf'ge resultant will be indicated.

1n devices of this class it is usually desirable to have an indicatorshowing the revolutions per minute operable at will and therefore 1 haveshown herein means to throw the average indicator showing reyolutionsper minute into a series of operatlve connections with the actuatingpart of the average indicator `and to enable such revolutionsper minuteto be set to indicate the average either for a less time than a minuteviz. thirty seconds, or for a greater time than one minute viz. for liveminutes.,

A still further feature of the invention consists in the arrangement andposition of the indicating rings and of the actuating and resetting`mechanism for the indicator which counts the revolutions per minute, aswill be hereinafter explained.

Although my invention is herein described as preferably applicable tothe several propelling shafts of a ship, it is of course not limited tosuch use but maybe employed to count and indicate the average number ofmovements of a plurality of any moving members, such as oscillating,vibrating, etc., in addition to rotating members such as shafts. f'

Further novel features of the invention, details of construction andcombinations of parts will be hereinafter more-particularly defined andclaimed.

A1n the drawings wherein a preferred embodiment of the invention isillustrated,

Figure 1 is a plan view of the indicators for three shafts in operativeconnection with an average counter and with a counter to indicate therevolutions per minute during a specified length of time;

Fig. 2 is a cross section on the line`2-2 of Fig. 1;

Fig. 3 is an enlarged detail of one of th counting mechanism;

Fig. 4 is a view in cross section on the line 4-'4 of Fig. 3;

\Figs. 5 and .6 are detailed views of the indicator rings; and

Fig. 7 shows the star wheel to actuate lthe rings; 4 i

Figs. 8, 9, and 10, illustrate details of the mechanism for determiningthe average revolutions per minute; and Fig. 11 is a fragment of adifferential gear; and

Fig. '12 shows the differential gear to transmit the average of thethree shafts to the average indicator; while Fig. 13 illustrates th(Lcompensating device to determine and transmit'the average of twoindicators;

Fig. 14 illustrates the compensating and differentiating transmissionmechanism to determine the average of four indicators and theirrespective shafts;

Figs. 15, 16, 17 are details partly in cross section of the modificationshown in Fig. 14;

Fig. 18 is a plan view of the cover for thek box containing theindicators shown in Fig. 1.

1n a preferred embodiment of the invention, illustrated in the drawingsI have shown a series of three indicators, to be connected with threerevolving shafts and the average indicator to determine the resultantaverage of said three indicator shafts and the whole mechanism beinginclosed in a suitable compact square box to be positioned in the chiefengineers department of a vessel. Such compartment isV usually adjacentthe engine room so that any suitable means to connect the propellingshafts with the respective shafts to actuate the several indicators maybe easily and conveniently effected. 1t is usual to designate theengines of a triple screw vessel for example'as numbers 1, 2 and 3 andthe respective rotation indicators may be similarly designated and namedaccording to the propelling shafts with which they may be connected.rlFherefore as herein shown therotation counters or indicators 1, 2 and3, intended to be operat1vely connected to propeller shafts num-`connection being of any well known type and not being a part of thisinvention need not be further described. rlhe box 5 is preferably madeof brass or other non-corrosive place against the flange 9 by the plate10 tion. A stud 19, also supported in the flange indicating ring 26.

as illustrated 'in Fig. 2 thus making a substantially dust proofreceptacle for the indi eating mechanism.

The several rotation counters or indicators on the shafts 1,'2 and 3 maybe of any suit` able and appropriatetype of rotation counters butpreferably are as herein shown consisting of the well known Veeder type,with certain improvements, being actuated successively through a seriesof internal star wheels. A brief description of the indicator on theshaft 2 will suiiice to explain the indicators, on each of the shafts.Referring to Fig. 3 the shaft 2 is suitably journaled in the hub 4 inthe side of the box 5, and in the partition 6 through the bearingtherein of the hub 11. The taper pin 12 passes through the hub 13 of thefirst or driving ring 14 securing it to the shaft 2. The hub 11comprises a loose sleeve supporting the shaft 2 and carries a barrel l5on which the several indicating rings are supported and may slide, saidbarrel portion being united to the sleeve or hub 11 by a flange 16 asshown in Fig. 3. The barrel 15 is prevented from moving with the shaft 2by engagement of the set screw 17 passing through a suitable aperture inthe flange 16 and being tapped into a threaded-socket A bored in thepartition 6. A washer 18 interposed between the flange 1.6 and partition6l acts to hold the barrel in longitudinal -posi- 16 carries the severalstarwheels which actuate the successive indicating rings. The firstindicating or driving ring 14, which is rotated with each revolution ofthe shaft 2, has two hardened steel teeth 20 and 21 on its innerperiphery as indicated in Fi 6 which teethV engage and actuate the ffrststar wheel 23 moving it the space of one number during each completerotation of the driving ring 14. The star wheel 23 being loosely mountedon the stud `19 and having its teeth in mesh with the internal gear onthe adjacent indicating ring 24 will move said ring the space of twoteeth or one nurnber during each complete revolution of the driving ring14 as will be readily understood. The ring 24 is similarly provided withtwo teeth to actuate the next adjacent star wheel 25 moving it the spaceof one number for each Y/complete revolution of the ring 24 said starWheel 25 being in turn in mesh with the teeth of the next adjacent Thisarrangement is substantially similar to that of the well known rotationcounters of the Veeder type as already mentioned excepting that in theVeeder type the indicating rings are mounted interiorly of, a casingwhich protects them. My improved construction is of special advantage ina rotation counter and indicator for marine work as, by providing theindicating rings outside of their supporting member said rings, whichalso Will'enable the engraving and lettering to be easily per# ormed,and which allows each indicating ring to have its inner rib 27 ofhardened steel for better wearing and to more accurately retain itsexactness of form than would be possible were the entire ring made.

of non-corrosive metal. teeth 20 and 21 of each of tempered steel andare fitted into corresponding sockets therefor in the rib portion 27 ofeach ring. By making the various parts of the indicating rings of thelbest material for the respective uses to which they are severally put,Iam able to produce a counter which can be manufactured advantageouslyand assembled withy `eat nicety so that, when so assembled, it will actwith absolute accuracy and last indelinitely, being almostindestructible and requiring no readjustments.

The arrangement and construction of all the counters are similar to thaton the shaft 2 just described and are similarly actuated. The threecounters on the shafts 1, 2 and 3 will count the rotations of theirrespective shafts and in order to count and indicate the average numberof revolutions of the Preferably the said three shafts I provide asimilar counter I am enabled to use lnon-corrosive material for ytheexterior of indicating ring are the side of the box 5 and the partition6 respectively, as indicated in Fig. 1. This average counter andindicator is actuated by the sprocket Wheel 31 which is secured to theshaft 28 by a taper pin 32 passing through the shaft and hub of thesprocket wheel. The mechanism yto determine `and to transmit the averageof the three indicators on shafts 1, 2 and 3 to the sprocket wheel 31and henceto the average indicator .on the shaft 28 will now bedescribed. It

will be noted that the partition 6 in' the box 5 is positioned slightlyto one side of the center and this ena/bles the compensating,differentiating and transmission mechanism to be located substantiallyin the central portion of the box 5 and midway between the` outsidebearings of the indicator shafts. The shafts 1 and 2 may be convenientlyjournaled in their butting end portions (see Fig. 13) and the shaft 2having a reduced p0rtion to engage a correspondingly bored socket in theshaft 1 and preferably a bushing 33 is interposed between the bearingportions and the shafts.. A gear wheel 34 'is loosely mounted on theshafts 1, and 2 at the interconnected joint just described which gearhas a radially mounted'pinion 35 of a greater diameter than the width ofpinion meshes with beveled gears 36 and 37 pinned to the shafts speedwith that of the shaft 2 it will bey 1 and 2 respectively. lt will beunderstood that the beveled pinion 35 is positioned 1n a suitableaperture 38a in the gear Wheel 34 as is illustrated in Fig. 2. Rotationof the shaft 2 in either direction will rotate the gear 34, whenthe'shaft 1 is at rest, through the engagement of the beveled gear 37with the pinion 35, moving the wheel 3 4 at a rate of speed equal toone-half the rate of speed of said shaft 2, as the'pinion 35 is in theradial center of the said wheel 34 and therefore the beveled wheels 36and 37 are equal distances from-the central diameter of the Wheel 34which passes through the axis of the pinion 35. 1f the shaft -1 is alsobeing rotated in the same direction and at the same readily seen thatthe gear wheel 34 will be also rotated at an equal speed through -theengagement of both gears 36 and 37 -with the pinion 35 and consequentlythe pinion 35 will be held rigidly, relatively with the gears 36 and 37and ,consequently the Wheel 34 will.

be positively rotated as just explained. lf the shaft 1 for example isbeing rotated in one direction and the shaft 2 in the reverse directionand both are rotatingv at the same rate of speed the wheel 34 willremain stationary as the pinion 35 will simply be rotated through itsengagement with the gears 36 and 37, which gears would also be moving inopposite directions. As the gea-r 34 is intended to transmit the averageresultant number of revolutions of the Ashafts l and 2, if said shafts,as just mentioned are rotating in opposite directions there would be noresultant average, and the gear 34 would be at rest. However, if theshaft\2 for example is beingsrotated in one direction and the shaft 1 isat rest the gear 34 moves at a rate of speed equal to one half that ofthe shaft 2 and hence makes one complete revolution during two completerevolutions of -the shaft 2. And similarly if the shaft l is beingrotated at the same speed and the same direction as the shaft 2 then theresultant average transmitted by the gear 34 will conl stitute onecomplete revolution of said gear 34 with each revolution of the shafts 1or 2 which, under this condition would be moving together practically asa solid shaft.

lt will also be readily appreciated that, for example, where the shaft 2is moving in one direction at a given speed and the shaft 1 in thereverse direction at a less speed the wheel 34 will be actuated'proportionately in the direction of rotation of the shaft 2, thedifference in speed between the gear wheel 36 and the Wheel 37 being theonly movement transmitted to the Wheel 34. Consequently the arrangement1 have shown of gears 36 and 37 engaging at diametrical opposite pointswith the teeth of the pinion 35 the stud 50 to being which pinion ispivoted to the gear 34, constitutes a compensating device to compensatefor and to transmit the resultant average number of revolutions of theshafts 1 and 2.

In the embodiment of the invention shown in Fig. 1 the gear 34 actuatesthe average counter on the shaft 28 through the engagement with thedifferential gear to be ,def

scribed. on the shaft 3 and thence through the sprocket wheel 31, but inthe form illustrated in Fig. 14 the gear wheel 34 may be connecteddirectly, or through an idler to preserve thesame direction of movementwith the shaft 28 and the average counter thereon.

Referring to the invention as applied' to three rotat-ing shafts, Ishownin Fig. 1, the shaft 3 carries a beveled gear 38 pinned thereto, andalso carries a sleeve 39 -on,

which sleeve is a sprocket wheel 40. Loosely mounted on the sleeve 39 isa differentiating rotation of the Wheel 34 will be exactly transmittedand in the same direction to the wheel 41 which wheel however is looselymounted on the sleeve 39. Secured to the sleeve 39 is a clamp 4 8 havinga clamping screw 49 and carrying a stud 50 on which stud is mounteddouble intermediate gears of different diameters 51 and 52, the latterbeing in mesh with the gear wheel 38 on the shaft 3 and 51 being in meshwith the beveled teeth 43 on the wheel 41 as clearly indicated in Fig. 12. Actuation of the gear 34 as previously explained will transmit theaverage rotation and speed offthe shafts 1 and 2-through the idler 44t`othe wheel 41 and byv the Wheel 41 will betransmitted throughitsengagement with the teeth 51 on the sprocket Wheel 40. A sprocketchain 53 connects the sprocket wheel 40 with the sprocket wheel 31 bothof the same siz'e and consequently actuating the shaft 28 and thecounter and indicator carried thereby in the same direction and speed asthatof the wheel 40. Actu- Yation of the shaft 3 will also rotate theating the operate the counter and indicator on the shaft 28 in theproportion of `1 and 3. Thus a complete revolution of the shaft 2 forexample will rotate the shaft 28 and the counter and indicator thereofone-third only of a revolution. Similarly the rotation of the shaft 3during one complete revolution While the others are at rest, through theengagement of the gear 38 and the intermediate gears 52 and 51" and thebeveled teeth 43 on the Wheel 41, will rotate the shaft 28 onethird onlyof a revolution, and consequently the rotation of shafts 1, 2 and 3 allin the same direction and at the same speed will actuate the counter andindicator on the shaft 28 one complete revolution for each revolutionthen made by'said shafts 1, 2 and 3, each shaft serving to turn theaverage counter a third of a revolution. The operation of my inventionis absolutely accurate and automatically, instantly and continuallyproduces, counts and indicates the average number of rotations of thethree shafts irrespective of their rates of speed or directions. Themechanism just described will, of course, not only produce theresultant-average for the number and speed of the rotations of theshafts 1, 2 and 3 when they are being rotated in the same direction butalso if one of said shafts is rotating in the reverse directions or ifall are going at different rates of speed. The proper proportions havingbeen produced between the actuating gears, all possible variations ofspeed, directions and number `of rotations will be necessarily averagedand indicated on the shaft 28.

The further important features of the invention whereby the averagenumber of revolutions per minute of a plurality of rotating shaftsiscounted and indicated, either during a minute, or during a less or -agreater period than a minute, will now be described. The shaft 28 beingactuated through the sprocket wheel 31 and the sprocket chain 54 at theaverage producedby the mechanism comprising the interconnected gearsopersleeve 39 and the sprocket 40, the

'average revolutions per minute can be taken to be in mesh with thedirectly from this shaft. Pinned to the shaft 28 is a gear. 55 in meshwith a coperatinggear 56 mounted on a sliding rod 57. This rod issuitably journaled in a bracket 58 and a sleeve 59 in the bearing in'the side of the box 5, extending beyond said box and carrying a thumbnut 60. Mounted adjacent to the rod 57 is an indicator comprisingl aseries of indicating wheels generally similar to the counter alreadydescribed and mounted on a stud secured tol the side ofthe box 5. Thefirst or driving ring of this indicator carries two gears Gland 62suitably keyed thereon. The gear wheel 61 be'ng arranged gear 56 on therod 57 when said rod is manipulated to slide the lThe gear 56 is of gear56 and 61 into operative connection. proportionate width so as to be 1nengagement with the gear 55 at all times within the limit of movementof` the rod 57, and the rotation of the shaft 28 will be transmittedthrough said gears 55, Y

56 and 61 to the indicator just mentioned, the wheel 61 being of suchproportion to the gears 56 and 55, (which latter are of equal diameter.)so that the indicator will be rotated at twice the speed of rotation ofthe 'shaft 28 and in the same direction therewith. Therefore thisindicator will show in thirty seconds, the number of average revolutionsper minute of the shafts 1, 2 and 3. In order to also determine theaverage number of revolutions per minute for a greater length of timethan one minute, as forexample in five minutes, the rod 57 carries agear 63 adapted to v'engage the gear wheel 62 when the rod 57 -is movedor slid along so as to bring the wheel 62 into mesh with the wheel 63.These wheels are of proper proportion so that five revolutions of theshaft 28 will rotate the gear 62 and consequently the indicator, duringone revolution and therefore the average number of revolutions for oneminute during a period of five minutes will be counted by the indicatorshowing what is the average revolution live minutes time. Anypredetermined ratio of time may be counted by providing properlyproportioned gear wheels other than merely for thirty seconds, and for afive minute interval, although these two are the per lminute during thesaid period of onesiI have found to be most'desired in the 1 presentuses to which my invention has been applied. In order to hold the rod 57where moved so that the desired gear will be ac-` with the slot in themember 65 or into engagement with the Walls of said slot if the pin isout ofthe notch. When therod 57 is slid so that the gears 56 and 61which are in mesh with the pin 64 will be at one end of the slot in saidmember 65, when gears 63 and 62 are in mesh the pin 64 must beat theother end of said slot and when said pin is in the notch the indicator'is disengaged from operative connection with the gears on the rod 57,and 4maybe reset. 0Any suitable resetting device may be employed butpreferably I use the novel form as herein shown.

The average. counter and indicator for the revolutions per minute willpreferably comprise only three indicating rings as oneto a. thousandrevolutions per minute may be Vio counted on three rings and this speedis seldom exceeded in propelling shafts, although of course any numberof revolutions per minute may be counted by providing a proper number ofrings. ln order to reset the devices the rst or driving ring may bequickly turned through the thumb piece 67 projecting outside the box 5and keyed to the supporting shaft of said indicator `which shaft has thewheels 61, 62 on its inner end. lin order `to reset the` third indicatorring T have arranged the sleeve 59 with a thumb.

piece 68 on its outer endand the gear wheel 69 on its inner end which isarranged to be meshed with a gear wheel 70 secured to said thirdindicating ring so that manipulation of the thumb piece 68 will rotatethe third ring of the indicator. A spring 71 secured to the side of thebox 5 normally throws. vthis resetting mechanism out by my averagecounter and indicator andl the counter for indicating the revolutionsper minute may be applied to a series of four shafts. Asn the indicatorshaft, rings, etc., in the case of four shafts would be like those shownin Fig. 1,-ll will simply describe, and have illustrated in Figs. 14517,the mechanism connecting the four individual shafts to the averagecounter andindicater shaft for the entire series.

Referring to Fig. 14 the end portions of shafts 78, 74, 75, and 76 willbe understoodl to be the shafts carrying individual counters andindicators similar to those already described in connection with shafts1, 2 and 3. The shaft 77 is that' carrying the average counter andindicator and 'corresponding to the shaft 28 already described. Thecompensating mechanism for the'shafts 75 and 76 are indicated clearly incross section in Fig. 16 and comprise a beveled gear 78 keyed to theshaft 7 5, a similar beveled gear 79 of equal diameter keyed to theshaft 76 and an intermediate beveled gear 8()` meshing with each of saidgears -78` and 79 and being radiallymounted in a spf'ocket wheel 81.This arrangement is similar to that already described in connection withthe compensating gear for the shafts 1 and 2. Preferably the shafts 75and 76' would have a bearing in the joining end'portions similar to thatillustrated in Figs. 13 and 15. The actuation of shafts 75 and 76 willresult in the transmission of the average number of 'revolutions to thesprocket Wheel 81 in a similar manner to that above mentioned inlconnectionkywith naaanaa the shafts 1 and 2. The sprocket wheel 81 isconnected by a sprocket chain with a corresponding sprocket wheel 82 ofequal diaman idler 87 mounted on a suitable shaft 88` between fixedcollars and is a-lso in mesh with a gear wheel 89 mounted loosely on thesupporting shaft 77 as indicated in Fig. 15. The gear wheel V89 and thesprocket wheel 82 are of similar diameter and each is intended to rotateat the average of two shafts produced by the respective connectionstherewith. Secured to the'shafts 77 between the gears 82 and 89 by aVscrew 90 is a stud 91 carrying a beveled gear 92 which gear is ofproportionate diameter to engage at diametrically opposite pointsthereon, the correspondingly beveled gears 93 on the wheel 89 and 94 onthe wheel 82. This arrangement is a compensating device, so that thelrotation transmitted through the sprocket wheel 82, when the gear 89for example is at rest, will rotate the average counter on the shaft 77through only bne half a revolution during a complete revolution of thesprocket 82. Tt will be remembered that a complete revolution of eitherof the shafts 75 or 76, while 'the other is at rest will result in onlyone half a revolution of the sprocket wheel 82 as has beenalreadyvexplain'ed in connecf tionjwith the shafts 1 and 2. Similarly acomplete revolution of the gear wheel -89 serves only to rotate one halfa revolution so that it will bev readily understood that the averageindicator- 'actuated by the through one fourt haftv 77 will be rotatedof a revolution duringv the shaft 77 through j each` complete revolutionof any one of the in- Y dividual shafts 73, 74, 75, or 76 while theothers are at rest. Therefore a proper average for all four of saidindicator shafts is f shown bythe counter carried by the shaft 77.

While the gear wheel .89 and sprocket Wheel 82 are normally arranged tobeloosely rotatab e on the shaft 77 I have provided a socket 95 throughthe hub of the wheel 89 and a similar set screw 96 for the wheel 82. Ifthe set screw 96 is shifted to the socket 95 and set to hold the Wheel89, the average number of rotations and rate of speed of the two shafts73 and 74 only will be transmitted to and indicated by the averagecounter and indicator on the shaft'7 7. Similarly if the set screw 96 isshifted to the socket 9.5 on the hub of the wheel 82, then the averageof the two other shafts 7 5, and 76 only be counted and indicated tionsper minute.

indicating the respective engines 1, 2 and 3 Whether the other shaftsare in motion or not. In order to suitably coverthe box or r-eceptacle 5a glass cover is provided as indicated'in "Fig, 2 and the plate 10 isalso provided as shown in Fig. 2 and Fig. 18 and with suitable openingsto permit the readings to be taken from the several individual countersand the average counter as well as from the indicatorshowing the revolu-The numbers l, 2 and 3,

towhich lthe three shafts illustrated in Fig. l. have been described asconnected therewith may conveniently be shown on the plate 10 andpreferably such numbers are interchangeable as it may be more convenientto connect the number l engine for example with one of the indicatorsnear the of the box than that at the left as shown in the drawings.supported on an arm 97 proximity to the indicator olutions per minutemay be provided whereby the fractions of revolutions per minute may bemore accurately read.

It should be noted that the rotation counters and indicators on eachlshafts l, 2 and 3, as well as on shafts 73,

74, 75, and 76 are unnecessary for the opernow If desired a scale andarranged in showing the reve' ation of the average counter and indicatoras well as unnecessary for the, operation of the indicator showing thenumber vof revolutions per minute. It is however convenient to haveeachlindividual shaft equipped with such a rotation counter and Ihavetherefore shown them thus provided. r

The operation of my invention has already been described andadvantages-will be readily appreciated. The invention provides anindicator capable of indicating the average revolutions per minute oftwo or more moving parts, and of counting and showing such averageinstantly, automatically and continuously, withoutydelay, withoutmathematical calculations of any-kind and withabsolute exactsuch periodsness and accuracy.v This resultant average is obtained irrespective ofthe direction or of the rate of rotation of any one individual member orwhether all or less than all members are in motion. -All three or moremembers may be moving at different rates of speed and' yet the resultantaverage is auto,- matically determined and indicated'. The provision ofs uch means is believed to be entirely novel and it is therefore desiredto claim the same broadly, as applied to a plurality of moving members.

Furthermore, the feature of the counting means to indicate therevolutions per minute for any given length of time whether shorter orlonger than a minute and with a choice of 'be absolutely right ofI theindividual it is believed that Aits operable at will is believedvtonovel as applied to any one rotation counter, and, therefore, thisfeature of the invention is not to be limited to an average counter fora plurality of moving `members but is intended to .be claimed broadly aswell as in combination with such an average counter.

Having described my invention, what I claim as new and desire to secureby Letters Patent is: Y

l. In apparatus of the kind described, the combination with operativeconnections from three propelling engines of a ship, of

separate `cpunter mechanism for each engine to indicate the number ofrevolutions of the respective engines, and an average indicator adaptedto be connected with each of the counter mechanisms for each shafttogether with means to compensate, automatically, for proportionatelydifferent rotative movements of any of said propelling engines and toproportionately actuate said average indicator.

2. In apparatus of the kind described, the combination with operativeconnections from three propelling engines of a ship, of separate countermechanism for each engine l to indicateIthe number of revolutions of therespective engines, and an average indicator adapted to be connectedwith each of the counter mechanisms yfor each shaft together withdifferential lgearing interposed between the propelling engines and theaverage indicator, said gearing being constructed andarranged toautomatically compensate for speeds and dissimilar directions in thepropelling engines and to'transmit the resultant average only of all ofsaid engines to the average indicator.

3. In apparatus'of the kind described, the combination with operativeconnections from three separate counter mechanism for each engine toindicate the number of revolutions per minute of the respective engines,and an average indicator adapted to be connected with each of thecounter mechanisms for each shaft together with differential gearingarranged to compensate, automatically, for proportionately differentrotative Inovements of any of said propelling engines and 'toproportionately actuate said average ilcator.

yet. In a device of the class described, a rotation counter adapted toindicate the average rotations of three or more individually .movingshafts capable of varying rates of speed and in dissimilar directions,and a shaft to be deducted, and the resultant average rotative movementof all ot said shafts to be transmitted to said average indicator.

5. lin a device of the class described, a rotation counter adapted toindicate the average rotations of. three or more individually movingshafts capable of varying rates of speed and in dissimilar directions,andy a dier'ential gearing connected to each one ot said individuallyactuated shafts, said dif- `erential gearing including a rotatablesleeve carrying an idler meshing with two independently rotatable gearsactuated by said shafts permitting the dissimilar rates of movements ofany two of said shafts, while another shaft is stationary, to beequated, and the resultant average rotative movement of all ot'saidshafts to be transmitted to said average indicator.

6. ln a device of the class described, an average indicator for aplurality orl diversely naaaoae moving members, consisting in three ormore moving parts, connections from each of said moving parts withrespective prime movers, compensating means connected with two .of saidmoving parts and adapted to show the combined average number ofrevolutions of' said two parts, in combination with dierential meansarranged to be actuated by a third moving part jointly with saidcompensating means and connections between the rotation counter and saiddierential means whereby the average number of revolutions of all ofsaid moving parts is transmitted to the rotation counter.

lin'testimony whereof, ll have signed my name to this speciiication, inthe presence of two subscribing witnesses.

HENRY H; CUMMlNGS.

Witnesses: I

` JAMES R. HOUDER,

R. d. HERSEY.

